Evaluation of Singrauli Coals for Sustainable Energy Utilisation: Insight From Geochemical and Petrographic Perspectives

Abstract

The study investigated 50 Permian coals from the Singrauli Coalfields in the Son Valley Basin, India, using advanced petro-geochemical techniques to assess their source rock properties, energy and utilisation potential and to reconstruct the paleodepositional environment. Petrological analysis indicated vitrinite reflectance values between 0.39% and 0.49%, classifying the Singrauli coals as sub-bituminous to high volatile bituminous rank and indicating a thermally immature state. The results of geochemical analysis (volatile matter: 36.8%–46.5% and T <inf>max</inf>: 420°C–425°C) further support the above contention. High carbon content (average 77.89%), low sulphur content (average 0.46%) and varying nitrogen and oxygen levels in studied coal enhance its environmental suitability. The hydrogen index (HI: 163–279 mg HC/g TOC) values suggest a predominance of type-III kerogen with mixed type-II–III kerogen, further supported by petrographic data. Moreover, geochemical and petrographic data suggested the suitability of Singrauli coals for gasification. The high total organic carbon (TOC ≥ 38 wt%) indicated admirable potential as a source rock for hydrocarbon generation, particularly within the gas-source rock zone, highlighting their suitability for energy production. Petrographic indices indicated a wet forest swamp origin with a telmatic source and bog region under ombrotrophic to mesotrophic hydrological circumstances. The association of macerals and total sulphur content further supported the conclusion of a freshwater environment during peat deposition. © 2024 John Wiley & Sons Ltd.